Abstract submission

ILD regularly submits abstracts to conferences on ILD and ILD re=
lated topics. Please find here a list of recently submitted abstracts, and =
their status. Once accepted as talks, you will find them under "talks".

Submitted abstracts

The CP nature of =
the Higgs and its couplings is imprinted on spin correlations between its d=
ecay products. We will present a method based on Higgs decays to tau lepton=
pairs, showing that the mixing between even and odd CP components can be m=
easured to a precision of 4.3 degrees at ILC-250. We will also show results=
on the expected measurement precision of the coupling between the Higgs bo=
son and tau lepton at ILC.

Higgs self-coupling measurement provides=
a direct probe of the Higgs potential, which is important both for underst=
anding of electroweak symmetry breaking and for testing of electroweak bary=
ogenesis. In this talk we will present studies addressing two issues about =
the Higgs self-coupling measurement at the ILC at the center-of-mass energi=
es of 500 GeV and 1 TeV. The first issue is about how model independent det=
ermination of the triple Higgs coupling is possible, provided that in a gen=
eral BSM theory the double Higgs production processes can receive correctio=
ns not only from the triple Higgs coupling but also from other Higgs coupli=
ngs. The second issue is a realistic estimation about the experimental prec=
ision on the double Higgs production cross sections, based on the full dete=
ctor simulation using the ILD and by including all SM background processes.=

The studies for the first issue are published on arXiv:1708.09=
079, while the paper for the second issue is in preparation.

Abstract: deviations in Higgs cou=
plings may not only appear in the strength of SM-like Higgs couplings, but =
also appear as distinct Lorentz structures, which is manifest in particular=
in the effective filed theory. In the case of VVH couplings (V=3DZ, W), on=
e new CP-even and one new CP-odd tensor couplings can be presented as anoma=
lous couplings. Experimental determinations of those anomalous VVH coupling=
s can provide new insights in probing the BSM models and finding new CP vio=
lating effects in the Higgs sector. This talk reports the experimental stud=
ies of anomalous VVH couplings at the ILC, emphasizing how the effects of e=
ach anomalous coupling and SM-like coupling can be distinguished and determ=
ined simultaneously by taking advantage of various angular distributions. T=
he results will be given based on the full detector simulation of the ILD a=
nd including major Higgs production and decay channels, for both Ecm=3D250 =
and 500 GeV at the ILC.

Part of the studies has been published on arX=
iv:1712.09772, a more comprehensive paper is in preparation.

We study the prospects for measuring the branching ratio of&n=
bsp;h=E2=86=92=CE=BC+=CE=BC=E2=88=92 at =
the International Linear Collider. The study is performed at center-of-mass=
energies of 250 GeV and 500 GeV based on full simulation of the Internatio=
nal Large Detector. For both center-of-mass energies, the two final states&=
nbsp;qq=
=E2=8E=AF=E2=
=8E=AF=E2=8E=AFh and =CE=BD=
=CE=BD=E2=8E=AF=E2=8E=AF=E2=8E=AFh have been analyzed. For an integrated luminosity o=
f 2 ab=
=E2=
=88=921=
&nbsp=
;at 250 GeV and 4 ab=E2=88=921=
span> at 500 GeV, the combined precision on the cross section times =
branching ratio of h=E2=86=92=
=CE=BC+=CE=BC=E2=88=92 is estimated to be 17.5%=
. The impact of the transverse mo=
mentum resolution on this analysis is also studied. A precision of 15%=
&nbsp=
;could be archived with 10 times better resolution, while a precision would=
increase to 25%=
with 10 times worse resolution.

Precision measurements of the properties of the=
Higgs boson, discovered by the ATLAS and CMS experiments of the LHC, and t=
he top quark, the heaviest known elementary particle, are among the main ph=
ysics goals for experiments at the proposed international linear collider (=
ILC). These measurements must reach an unprecedented level of precision to =
allow us to decipher the next fundamental layer of physics, called new phys=
ics. The vertex and tacking detectors of the ILC experiments will be a key =
towards accomplishing the ambitious physics programs of the latter. We disc=
uss the design requirements of these state-of-the-art detector systems, dri=
ven from the stringent physics and experimental constraints of the ILC.

Study of the Higgs couplings to leptons and Higgs CP properties=
at the ILC

In the=
Standard Model the many Yukawa couplings between the Higgs and fermions, r=
esponsible for the mass generation for fermions, are predicted to be strict=
ly proportional to the masses of fermions. Any deviation from this predicti=
on would clearly signal new physics beyond the SM. Many alternative ways of=
introducing Yukawa couplings in BSM models can result in quite different c=
haracteristics for different types of fermions, e.g. upper- or down-type, l=
epton- or quark-type, 3rd-, 2nd- or 1st-generation. More over, if the SM-li=
ke Higgs is an admixture of CP even and CP odd states, as preferred in the =
electroweak baryon genesis models which can potentially explain the baryon =
number asymmetry in our universe, the Higgs Yukawa couplings will be modifi=
ed at the tree level. In particular the Higgs to tau tau decay process prov=
ides an ideal place for probing the Higgs CP properties. In this talk, we w=
ill give the prospects about the measurements of Htautau and Hmumu coupling=
s at the International Linear Collider (ILC), including the Higgs CP phase =
measurement in Higgs to tautau process using a novel tau reconstruction met=
hod. All the simulation studies are performed based on the full detector si=
mulation for the International Large Detector (ILD).

Search for Light Scalars Produced in Association with a Z boson=
at the 250 GeV stage of the ILC

In many models with =
extended Higgs sectors, e.g. in Two Higgs Doublet Models, in the NMSSM as w=
ell as in Randall Sundrum models, there exists an additional scalar h, whic=
h can easily be lighter than the Standard Model (SM) like Higgs. Its coupli=
ng to the Z boson is expected to be small if the 125 GeV Higgs boson is SM-=
like. Such a light scalar with suppressed couplings to the Z boson would ha=
ve escaped detection at LEP due to its limited luminosity. With a factor of=
1000 higher luminosity and polarized beams, the International Linear Colli=
der (ILC) is expected to have substantial discovery potential for such stat=
es. Furthermore, searches for additional scalars at LEP and LHC are usually=
dependent on the model details, such as decay channels. Thus, it is necess=
ary to have a more general analysis with model-independent assumptions.=
We present a search for a such a light higgs boson produced in association =
with Z boson at the ILC with a center-of-mass energy of 250 GeV, using the =
full Geant4-based simulation of the ILD detector concept. In order to be as=
model-independent as possible, the analysis is performed using the recoil =
technique, in particular with the Z boson decaying into a pair of muons. Ex=
pected exclusion cross section limits for different higgs masses between 10=
and 120 GeV will be given in terms of a scale factor with respect to the S=
tandard Model Higgs-strahlung process cross section.

3rd Generation Quark and Electroweak Boson Couplings at the 250=
GeV stage of the ILC

The 3rd generation quarks are, due to their large mass, highly se=
nsitive probes for new physics connected to the electroweak symmetry breaki=
ng. While top quark pair production requires center-of-mass energies of lar=
ger than 350 GeV, the first stage of the ILC at a center-of-mass energy of =
250 GeV can perform precision measurements of bottom quark pair production,=
thereby settling the long standing ~3\sigma tension between the LEP experi=
ments and SLD. For this measurement, the polarised beams of the ILC are of =
special importance as they enable the separation of the vector and axial-ve=
ctor couplings of the b quark to Z boson and photon. Another important prec=
ision probe for new physics are triple gauge boson coupings (TGCs). Thanks =
to the polarised beams and the much higher luminosity, a significant increa=
se in precision beyond past and present experiments is expected at the firs=
t stage of the ILC for the TGCs involving W bosons. For both measurements, =
we will report recent projections based on detailed simulations of the ILD =
detector concept, and highlight the role of important detector performance =
aspects, e.g. for the separation of b and anti-b jets based on vertex charg=
e measurements and particle ID.

Study of the Higgs couplings to leptons and Higgs CP properties=
at the ILC

In the Standard Model the many Yukawa coupling=
s between the Higgs and fermions, responsible for the mass generation for f=
ermions, are predicted to be strictly proportional to the masses of fermion=
s. Any deviation from this prediction would clearly signal new physics beyo=
nd the SM. Many alternative ways of introducing Yukawa couplings in BSM mod=
els can result in quite different characteristics for different types of fe=
rmions, e.g. upper- or down-type, lepton- or quark-type, 3rd-, 2nd- or 1st-=
generation. More over, if the SM-like Higgs is an admixture of CP even and =
CP odd states, as preferred in the electroweak baryon genesis models which =
can potentially explain the baryon number asymmetry in our universe, the Hi=
ggs Yukawa couplings will be modified at the tree level. In particular the =
Higgs to tau tau decay process provides an ideal place for probing the Higg=
s CP properties. In this talk, we will give the prospects about the measure=
ments of Htautau and Hmumu couplings at the International Linear Collider (=
ILC), including the Higgs CP phase measurement in Higgs to tautau process u=
sing a novel tau reconstruction method. All the simulation studies are perf=
ormed based on the full detector simulation for the International Large Det=
ector (ILD).

Search for Light Scalars Produced in Association with a Z boson=
at the 250 GeV stage of the ILC

In many models with =
extended Higgs sectors, e.g. in Two Higgs Doublet Models, in the NMSSM as w=
ell as in Randall Sundrum models, there exists an additional scalar h, whic=
h can easily be lighter than the Standard Model (SM) like Higgs. Its coupli=
ng to the Z boson is expected to be small if the 125 GeV Higgs boson is SM-=
like. Such a light scalar with suppressed couplings to the Z boson would ha=
ve escaped detection at LEP due to its limited luminosity. With a factor of=
1000 higher luminosity and polarized beams, the International Linear Colli=
der (ILC) is expected to have substantial discovery potential for such stat=
es. Furthermore, searches for additional scalars at LEP and LHC are usually=
dependent on the model details, such as decay channels. Thus, it is necess=
ary to have a more general analysis with model-independent assumptions.=
We present a search for a such a light higgs boson produced in association =
with Z boson at the ILC with a center-of-mass energy of 250 GeV, using the =
full Geant4-based simulation of the ILD detector concept. In order to be as=
model-independent as possible, the analysis is performed using the recoil =
technique, in particular with the Z boson decaying into a pair of muons. Ex=
pected exclusion cross section limits for different higgs masses between 10=
and 120 GeV will be given in terms of a scale factor with respect to the S=
tandard Model Higgs-strahlung process cross section.

3rd Generation Quark and Electroweak Boson Couplings at the 250=
GeV stage of the ILC

The 3rd generation quarks are, due to their large mass, highly se=
nsitive probes for new physics connected to the electroweak symmetry breaki=
ng. While top quark pair production requires center-of-mass energies of lar=
ger than 350 GeV, the first stage of the ILC at a center-of-mass energy of =
250 GeV can perform precision measurements of bottom quark pair production,=
thereby settling the long standing ~3\sigma tension between the LEP experi=
ments and SLD. For this measurement, the polarised beams of the ILC are of =
special importance as they enable the separation of the vector and axial-ve=
ctor couplings of the b quark to Z boson and photon. Another important prec=
ision probe for new physics are triple gauge boson coupings (TGCs). Thanks =
to the polarised beams and the much higher luminosity, a significant increa=
se in precision beyond past and present experiments is expected at the firs=
t stage of the ILC for the TGCs involving W bosons. For both measurements, =
we will report recent projections based on detailed simulations of the ILD =
detector concept, and highlight the role of important detector performance =
aspects, e.g. for the separation of b and anti-b jets based on vertex charg=
e measurements and particle ID.

The International Large Detector (ILD) is=
a detector concept for the International Linear Collider (ILC), a 250-500 =
GeV (extendable to 1 TeV) center-of-mass high-luminosity linear electron-po=
sitron collider. The ILD is optimized with the concept of particle flow for=
overall event reconstruction so that it will deliver excellent performance=
for high-precision Higgs and top measurements, as well as high-sensitiviti=
es for possible new phenomena, utilizing the advantages of an electron-posi=
tron collider. Particle flow implies that all particles in an event, charge=
d and neutral, are individually reconstructed. This requirement has a large=
impact on the design of the detector, and has played a central role in the=
optimisation of the system. Superb tracking capabilities and outstanding d=
etection of secondary vertices are other important aspects. The overall lay=
out, sub-detector technologies, expected performance, and recent progress o=
f the ILD will be presented.

The International Large Detector (ILD=
) is a detector concept for the International Linear Collider (ILC), a 250-=
500 GeV (extendable to 1 TeV) center-of-mass high-luminosity linear electro=
n-positron collider. The ILD is optimized with the concept of particle flow=
for overall event reconstruction so that it will deliver excellent perform=
ance for high-precision Higgs and top measurements, as well as high-sensiti=
vities for possible new phenomena, utilizing the advantages of an electron-=
positron collider. Particle flow implies that all particles in an event, ch=
arged and neutral, are individually reconstructed. This requirement has a l=
arge impact on the design of the detector, and has played a central role in=
the optimisation of the system. Superb tracking capabilities and outstandi=
ng detection of secondary vertices are other important aspects. The overall=
layout, sub-detector technologies, expected performance, and recent progre=
ss of the ILD will be presented.

Sensitivity to anomalou=
s VVH couplings at the ILC (submitted by Tomohisa Ogawa)

The discovery of the 125 GeV Higgs boson, which was the last mis=
sing element of the standard model (SM), provided us the insight that the e=
lectroweak symmetry breaking is done by a Higgs condensate in the vacuum, n=
amely the Higgs mechanism. However the SM does not give the dynamics explai=
ning why and how that Higgs condensate is formed. On the other hand, the SM=
can not provide candidate particles for the dark matter, and can not expla=
in the baryon number asymmetry in our universe, etc. Therefore new physics =
beyond the SM is needed to answer all of those questions. Remarkably the ef=
fects of new physics will be inevitably imprinted in the properties of the =
Higgs boson, namely its couplings to other SM particles and its CP nature. =
At the future International Linear Collider (ILC), one of the most importan=
t goals is precise measurement those properties.

In this talk, we wil=
l focus on the measurement of the general Lorentz structure of couplings be=
tween Higgs and vector bosons (VVH, V=3DZ or W) at the ILC, based on an app=
roach of the effective field theory. The sensitivities to both CP-even and =
CP-odd dimension-5 operators are evaluated by exploring various Higgs produ=
ction and decay channels, in particular taking advantage of the sensitiviti=
es from differential cross sections measurements. The studies are performed=
based on full detector simulation of the International Large Detector (ILD=
), for ECM =3D 250 GeV and 500 GeV. Combined sensitivities are given for so=
me realistic running scenarios of the ILC.

In absence of a direct discovery of new =
particles, precision measurements of the properties of known particles will=
provide the most powerful probe for phenomena beyond the Standard Model. F=
uture electron positron linear colliders with polarised beams, like the Int=
ernational Linear Collider (ILC), will provide a unique laboratory for such=
measurements, complementary to hadron colliders. In this contribution, we =
will review in particular the prospects for electroweak precision measureme=
nts, like the mass of the W boson, or the weak mixing angle, as well as for=
measurements of charged triple gauge couplings based simulations of the IL=
D detector concept for the ILC. In all of these, the exact knowledge of the=
beam polarisation and the beam energy plays an important role. Therefore w=
e will also discuss the precision determination of these accelerator parame=
ters from collision data. We will pay special tribute to the most recent di=
scussions concerning a possible first stage of the ILC operating at a cente=
r-of-mass energy of 250 or 350 GeV, but also comment of the full ILC runnin=
g plan.

The heavy q=
uark doublet plays a central role in the quest for new physics. The complem=
entary between studies of electroweak top quark production and bottom quark=
production is therefore intuitively clear and pointed out in the literatur=
e. Let us remind that the tension between the LEP measurement and the Stand=
ard Model prediction of the forward-backward asymmetry $A_{fb}^b$ is still =
one of the unsolved questions in the field and may be interpreted as a firs=
t manifestation of new physics in the heavy quark sector. The process $e^+ =
e^- \rightarrow b\bar{b}$ at the ILC offers a unique opportunity for a fina=
l word on the tension. Polarised beams allow for a large disentangling of t=
he coupling constants or form factors that govern the $\gamma/Z \,b\bar{b}$=
vertex.

The contribution =
will present a detailed simulation study of the process $e^+ e^- \rightarro=
w b\bar{b}$ at 250\, GeV with the ILD Detector. Besides the phenomenologica=
l implications, the contribution will demonstrate that with a careful analy=
sis of the final state the charge of the b-quarks can be determined on an e=
vent-by-event basis with the ILD Detector. Such a capability is unprecedent=
ed by past and present particle physics experiments.

04.13.2017

A (poster), presenter: Sviatoslav Bilokin

5

Naturalness and light Higgsinos: why ILC is the right machine f=
or SUSY discovery (submitted by Jacqueline Yan)

Radiatively-driven natural Supersymmetry, =
a theoretically and experimentally well-motivated framework, centers around=
the predicted existence of four light, nearly mass-degenerate Higgsi=
nos with mass $\sim 100-200$ GeV (not too far above $m_Z$). Their small mas=
s splittings of at most 20 GeV implies very little visible energy of accomp=
anying Standard Model particles decayed from heavier Higgsinos. Given that =
other SUSY particles are considerably heavy, this makes detection challengi=
ng at hadron colliders. On the other hand, the clean environment of an elec=
tron-positron collider with $\sqrt{s}>2m_{Higgsino}$ would enable =
a decisive search of these required Higgsinos, and thus either the discover=
y or exclusion of natural SUSY. We present a detailed simulation stud=
y of precision measurements of Higgsino masses and production cross section=
s at $\sqrt{s}$ =3D 500 GeV of the proposed International Linear Coll=
ider currently under consideration for construction in Japan. The study is =
based on a Geant4 simulation of the International Large Detector conc=
ept. We examine several benchmark points just beyond the HL-LHC reach=
, with a mass spectrum containing four light Higgsinos directly accessible =
by the ILC, and the mass differences between the lightest SUSY particle and=
the heavier states ranging from about 4 to 20 GeV. It can be shown that th=
eir masses and production cross sections are able to be precisely measured =
to approximately 1% precision or better. These precise measurements allow f=
or extracting the underlying weak scale SUSY parameters. The fitted paramet=
ers give predictions for the masses of heavier SUSY states, which provide m=
otivation for future high-energy colliders. Additionally, dark matter prope=
rties may be derived. Evolution of the measured gaugino masses to high ener=
gies should allow one to distinguish the hypothesis of gaugino mass unifica=
tion from other compelling possibilities such as mirage mediation.=
p>

Natural SUSY at the ILC=
: from MZ to the GUT scale (submitted by Mikael Berggren)

Th=
e most basic requirement for naturalness in supersymmetric models is the ex=
istence of rather light partners of the Higgs boson, the Higgsinos, at mass=
es not too far above M_Z. Despite the pressure from LHC data on the simples=
t high-scale models (like the cMSSM), such light Higgsinos can still be rea=
lised in different types of GUT-scale models from NUHM2 to mirage unificati=
on models. The ILC will offer the unique discovery potential for the elusiv=
e higgsino particles and allow for precision measurements of their properti=
es. In this contribution, prospects for the achievable precisions for masse=
s, the very small mass splittings and polarised production cross sections w=
ill be presented. Based on these, we studied the possibilities to determine=
the SUSY parameters at the weak scale, and to extrapolate their running to=
the GUT scale. We will discuss the prospects to thereby differentiate betw=
een various GUT-scale models and SUSY breaking schemes and to predict the m=
asses of the remaining SUSY particles. In particular the latter could provi=
de important guidance for the energy scale of the next hadron collider afte=
r the LHC.

Future e+e- colliders offer excellen=
t possibilities for precision studies in the Higgs sector due to the clean =
experimental conditions and low backgrounds compared to hadron colliders. A=
t lower energies i.e. below 500 GeV, the Higgstrahlung is the dominant Higg=
s production mechanism. With the recoil mass analysis technique being the u=
nique feature of e+e- colliders, the Higgstrahlung allows model-independent=
studies of the Higgs couplings as well as the access to the invisible Higg=
s decays. If considered simultaneously with WW-fusion dominating Higgs prod=
uction at higher energies, determination of the Higgs total width is possib=
le at a percent level. Scalar sector searches are reviewed for ILC and CEPC=
using recent research updates obtained with the fully simulated ILD and CE=
PC detectors.

02.01.2017

A, speaker: Junping Tian

2

ILD for the International Linear Collider (submitted by Kiyotomo Kawagoe)<=
/span>

The Inte=
rnational Large Detector (ILD) is a detector concept for the International =
Linear Collider (ILC), a 250-500 GeV (extendable to 1 TeV) center-of-mass h=
igh-luminosity linear electron-positron collider. The ILD is optimized with=
the concept of particle flow for overall event reconstruction so that it w=
ill deliver excellent performance for high-precision Higgs and top measurem=
ents, as well as high-sensitivities for possible new phenomena, utilizing t=
he advantages of an electron-positron collider. Particle flow implies that =
all particles in an event, charged and neutral, are individually reconstruc=
ted. This requirement has a large impact on the design of the detector, and=
has played a central role in the optimisation of the system. Superb tracki=
ng capabilities and outstanding detection of secondary vertices are other i=
mportant aspects. The overall layout, sub-detector technologies, expected p=
erformance, and recent progress of the ILD will be presented.

01.17.2017

R (Our abstract is merged with tha=
t of CLICdp for a more general talk.)

<=
/span>The International Large Detector (ILD) is a detector concept for the =
International Linear Collider (ILC), a 250-500 GeV (extendable to 1 TeV) ce=
nter-of-mass high-luminosity linear electron-positron collider. The ILD is =
optimized with the concept of particle flow for overall event reconstructio=
n so that it will deliver excellent performance for high-precision Higgs an=
d top measurements, as well as high-sensitivities for possible new phenomen=
a, utilizing the advantages of an electron-positron collider. Particle flow=
implies that all particles in an event, charged and neutral, are individua=
lly reconstructed. This requirement has a large impact on the design of the=
detector, and has played a central role in the optimisation of the system.=
Superb tracking capabilities and outstanding detection of secondary vertic=
es are other important aspects. The overall layout, sub-detector technologi=
es, expected performance, and recent progress of the ILD will be presented.=

12.12.2016

R (T. Omori gives a more general t=
alk on behalf of LCC: "Status and Future Perspectives of the ILC Project: A=
ccelerator / Detector R&D".)